Regular sex 'cuts prostate cancer risk'

Regular sex can help protect men against prostate cancer, a medical study has found.

It showed that the most sexually-active males had less chance of contracting the potentially-fatal disease.

Frequent sex was also linked to less aggressive prostate cancer, which is more likely to respond to treatment and has a lower likelihood of spreading.

The research by experts in Boston involved nearly 30,000 men - all health professionals - aged between 46 and 81.

Doctors asked about them about their ejaculations in their 20s, 40s and during the previous year - 1991. Over the next eight years, 1,449 men developed prostate cancer, says a report published yesterday in the Journal of the American Medical Association.

On average, the men overall had four to seven ejaculations a month. However, no increased risk of prostate cancer was seen in males who reported more frequent experiences.

The two highest activity levels - 13 to 20 a month and at least 21 a month - were each linked with decreased cancer risks of 14 per cent and 33 per cent.

Cancer-causing chemicals

Researchers think that the activity has a protective effect because the prostate secretes the bulk of the fluid in semen, and sexual activity may flush out cancer-causing chemicals.

Another theory is that it reduces the development of calcifications in the gland that has been linked with cancer.

However, more research was needed because relatively few men in the study reported heavy sexual activity, said Dr Michael Leitzmann, of the National Cancer Institute, who led the survey.

He added: 'It's too early to suggest men should change their sexual habits to alter their prostate cancer risk.' The cancer is now the most common form of the disease in men, with around 20,000 cases a year in Britain.

Previous studies found that males who have frequent ejaculations might be more prone to the cancer. But it appears this is because some sexual infections may trigger the disease, rather than the act itself.

Predicting risk

It remains unclear whether there might still be a connection between frequent sexual activity and prostate cancer, as high levels of the male hormone testosterone fuel a strong sex drive and can also boost the growth of cancer cells.

Two new tests may predict which men might be most at risk from colon cancer and those most likely to die from prostate cancer if surgery or radiation fails, report U.S. researchers.

Men with long-term high levels of C-peptide - an indicator of insulin production triggered by high-fat diets and obesity - are said to be at triple the risk of developing bowel cancer.

A separate study found Prostate Specific Antigen blood test results after cancer treatment could predict patients most at risk of dying from the disease.

Both studies were published yesterday in the Journal of the National Cancer Institute.